Various types of flow-rate adjustable valves using valve bodies have been used widely. In addition, it is disclosed in JP-A-H11-325274, for example, to restrict the stroke of a valve body to a desired range.
The flow-rate adjustable valve disclosed in JP-A-H11-325274 includes: a stepping motor; a threaded cylindrical member (lifter) linearly movable via a screw mechanism by a rotation of a rotational shaft of the stepping motor; and a valve body movable by a movement of the threaded cylindrical member. A rotational stopper restricts a rotational range of the screw mechanism. As a result, the movable range of the threaded cylindrical member is restricted, i.e., the movable range of the valve body is restricted.